Sheet-metal shears



0. DE w. WAGNER.

SHEET METAL SHEARS.

APPLICATION FILED JULY 3,1920.

Patented Mar. 28, 1922.

2 SHEETS-SHEET I.

C. DE W. WAGNER.

SHEET METAL SHEARS.

. APPLICATION men JULY 3. 1920.

1,410,972. v Patented Mar-28, 1922.

. V 2 SHEETS-SHEET 2.

airs FATENET OFFICE.

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by a purely mechanical operation.

The invention embodies certain improvements in the art of shearing sheet metal, for which Letters Patent numbered 801,697 and 935,072 were issued to me October 10, 1905," and September 28, 1909, respectively. Said patents relate to throatless shears for cutting comparatively thin metal, the shear being rnanually pushed or pulled across the sheet. In this case it' is possible to place the rollers which co-operate with the shear guide in a position perpendicular to the the cutting line.

sheet and with the guide-track practically in In the present invention provision is made for the shearing of much heavier stock by means of stationary shears, to which considerable power must be applied. The construction of such shears makes it necessary to arrange any guiding apparatus lateral to the cutters, and this has presented certain difficulties which, so far as I am aware, have not been solved heretofore.

The invention is fully set "forth and claimed in the specifications following, reference being had to the accompanying drawings, in, which Fig. 1 is a side elevation of a hand-operated, throatless shear, with my shearing guide attached. Fig. 2 shows in perspective the guiderollers and a mounting block there for attachableto the shear body. Fig. 3 illustrates the method by which I determine the proper setting of the guide rollers. Fig. 4 shows diagrammatically the proper setting of the rollers, and the relation of a (curved guide-track thereto. Fig. 5 shows a typical guide-track or template, and a simple manner of locating the same on a sheet and attaching it thereto. Fig. 6 isa plan View of a template, illustrating the fastening of a sheet thereto in the middle. Fig. 7 shows another way of so fastening the template to the sheet.

Specification of Letters Patent. W131, Application filed July 3, 1920. serial No; 393,837.

In thedrawing, the numeral 5 denotes a bench shear, of the rotary cutter, throatless type, and now in common use. The cutters (5; are n ountedon diagonal arbors, and one of the arbors is driven by gears 8 and 9 and a hand-wheel 10. In practice one of the cutters is serrated, thus dispensing with gears to connect the arbors, but this forms no part of the present invention. It is to be noted, however, that in order to give a shearing action to the cutters, the arbors are skewed a little in relation to each other, as shown in Fig. 3. The shear is adapted for the cutting otmuch heavier stock than is commonly employed in. furnace and the like tinsmith work, but hitherto no meanshave been providedfor guiding the sheet, except by the hand and eye, following a scratched line.

This is both slow, andinaccurate, whereas for duplicate work both speed and accuracy aredemanded. This I accomplish by means of templates clamped to the parent sheet, which template co-operates with; guiderollers, as will'now be described.

Laterally adjacent to the cutters, and preferably asnear to them as is practicable,

is mountedaset of four rollers 11, with their axes 12 practically perpendicular to the parent sheet 13 as it is cut. A simple mount for the rollers is shown in Figs. 1 and 2, and comprises astirrup-block 1 which isbolted to the shear body at 15. One pair of rollers is mounted by .its axes permanently on the block. The other pair should be mounted adjustably ,thereto. A simple device is shown the same being a short bar 16, to which the roller-studs or aXes are attached, and located in a recess 17 in the block, Where it is held adjustably by means oftensionscrews 18 and a set-screw 19. By this means the spacing between the pairs of rollers may be adjusted nicely to the Working requirements, and more loosely'with respect to the guide-rib ofthe template as its curvature increases. The template itself is a plate of sheet metal 20 provided with an upstanding rib:21, to run between the pairs ofrollers, and so. guid the parent sheet in its proper course while being cut. The true shape, of this 'guiderib with respectto the form to be cut will be described presently.

The proper setting, of the rollers in relation to the shearingcuttersis a. matter of great nicety, since any deviation from the exact position will cause the cutters to crawl, running in or out from their proper course, as the case may be. NVhen heavy stock is being cut, this crawl of the clination to swerve to either shears not only spoils the work, bntmay break or bend the guiding apparatus, or even break the cutters themselves. Once the rollers are properly set, however, all this adverse tendency of the cutters is .eliminated, and the shearing, either in straight lines, ormoderate curves, isperfeetly smooth and clean.

My experience tends to show that thisv cannot be-done theoretically, but must be 1 determined experimentally; The. skewof the cutter arbors; the size of the cutters;;

their hip in cutting, and other factors so complicatethe problem that it is practically impossible to.SOlVe it' geometrically. The

experimental test is .very simple, however,

and is indicated in .Figs. 3 and 4. On a test-plate line a I); This should, for convenience,

exactlyparallel with one of the sides of the plate. With the plate held lightly in one hand, the operator now passes it through the shear, guiding it sufiiciently for the shear to follow naturally, and with no inside, the

' scratched line, which thus becomes the .line

of leastydeflection; This line, as indicated in Fig. 3, will approximate a bisection of the angle'oi the cutters to each other, shown by the lines 0 (Z and? f. With the testplate in this neutral position, the guide rollers are set as indicated in Fig- 4:, the

longitudinal rollers exactly parallelwith the scratched line-in its relation to the cutters,

and the transverse pairs of rollers equidistant from the cutting point ofthe cutters, these lines being 9 h, 2' y', and is Z respectively. "The guide-rollersbeing thus fitted accurately to the shear, it may be depended upon for satisfactory work indefinitely.

The rollers being spaced away laterally from the'cutting line, it is evident the curve of the template guide-rib will vary from that of the line as cut. Accordingly allowance must be made for this diiference in forming the guide-rib. A simple method is to cut a pattern accurately along line,T guiding the sheet by hand. Then form the guide-rib to'a line parallel with the cut outline, andspacediaway therefrom to correspond with the space between said rib and the cutters when in use. The edge of the i template is trimmed away a little, after the" guide-rib is attached, which may be by soldering.

It will beseen by reference to 5 that the template is made a little longer than the widthfof the parent sheet,fso as to seat the guide-rib between the rolls in starting and 22 is scratch'eda perfectly'straight iinishing the cut. The template convenient-ly attached to the parent sheet by clamps in the case of a pieceof work that is long and slender it is sometimes desirable to 1 clamp it in the middle, as well as at the ls Thi b l b '1' en s may e cone y provlclng a wide template, as 1n Fig. 6, with a hole at to receive theclanip, or by attaching an extension 26, as shown in Fig. 7. This additional clamping effectually prevents any buckling in the case mentioned above.

In Fig. 5 is also shown a convenient gauge tor setting the template on the parent sheet, for the saving of tim in duplicate work.

i uidesboard 27 is provided with step- A P: pins 28 and 29 to locate the parent sheet, and with stops 30, 31 and 32 to engage the template as laid on said parent sheet in position for clamping thereto. By these means duplicatetorms of sheet metal may be produced very rapidly, and with a high degree of accuracy. r

Having thus described my invention, I claim: 7

l. The described method of and means for producing duplicate sheet-metal forms withv rotary shears, which comprises atemplate provided with an upstanding gandeerib,

. gnideerollers with parallel axes to straddle sad guide-rib, and a parent sheet se cured to aid template, the rollers being located laterally of the cutting line, and parallel to theline'of least deflection in making the 2. A. cutting guide for'rotary' sheet-metal shears, comprising two pairs of rollers, set

straddle said rib. a fixed mount or support for one pair Oii-tlIGTOllQIS, to hold them ;lateral to and parallel with the ascertained cutting lineof least deflection, and a laterally adjustable support for the other pair of rollers attached to the first, mentioned support.

In testimony whereof I aiiix my. signature in presence oftwo wltnesses.

' CLINTON DEWVITT WAGNER.

. itnesses;

R. D. BROWN,

guide for rotary shears, com- 

